Engineers retaliate with a PDP-11 OS hack

Engineers get back at a co-worker with what is probably one of the first "shells" used on an operating system--that had a very unique purpose

Engineers get back at a co-worker with what is probably one of the
first “shells” used on an operating
system--that had a very unique purpose

This story is for the people who remember the RSX-11 operating system
(DEC PDP-11)and enjoy a good tale about engineering ingenuity and
practical jokes. I worked for a company the used PDP11s as an embedded
computer in a test system. RSX-11
was a multiuser operating system that had (as all computers in the late
70's did) a simple
ASCII CLI.

The multiuser nature of RSX-11 was actually very handy in a
test system because
you could initiate a test and run additional processes to see the
progress, or do detailed
analysis of specific results, etc.

Also working for this company was a marketing person (we'll call him
Dave) who had little
respect for boundaries. He had a bad habit of coming down to the
engineering lab to do
demos for customers and even sometimes just his friends. The problem is
he often interrupted a
test that was running overnight to show off his skill at operating the
tester. As you might
expect this caused a significant amount of friction between engineering
and Dave.

The solution the engineers came up with was EDGAR (I have forgotten
what the acronym
stood for). EDGAR was a shell, if you will, that disabled the CLI and
intercepted all CLI
functions. EDGAR had a few special properties. It disabled the ability
to start and stop
other processes. It changed the command syntax, just a little.

And it
had a special
error handling function. It kept track of the number of errors, and its
reply got more
obnoxious as the errors increased. Normally RSX-11 just printed ^^^^^
under the portion
of the command line it did not understand. EDGAR would suggest
additional remedial
education, cast dispersions about your parenting, and suggest you go
and find
someone with an IQ above 50 to operate the equipment.

The engineers left EDGAR guarding their test and went to dinner.
They returned later
to find Dave screaming at the terminal, pounding on the keyboard and
nearly in cardiac
arrest. They told him that this was the new test operating system being
shipped with the systems (just for that final twist). He went away, and
EDGAR became a fixture of the
lab environment for some years to come.

Author Chuck Hill has 30
years design
experience in storage, and telecom
fields. He
has a Master’s Degree in Engineering from Arizona State University, and
a Master’s
Degree in Business from DeVry University.

Do you have a good example of an engineering practical joke? We'd love to hear about it and you could earn a cool $100! Extra credit if your story makes us laugh out loud. Email brian.fuller@ubm.com

The EDGAR story reminds me of my first job out of college. We used Nova 3s for the test stations and every software engineer carried their own operating system on (yes really) 5M removable disks. On particularly unique engineer had modified most of the commands and prompts on his version of the OS to some VERY rude alternatives. Well you knew it was bound to happen sooner or later, sales was escorting a potential new customer around the labs and ran across a system running Dave's OS (fake name). The attempts by the salesman to highlight system features were to say the least very PROVOCATIVE.. Next day a memo went out (yes, no emails then only hard copy paper) indicating to all staff that ONLY the standard OSes would be allowed due to a public relations problem caused by a "rogue" OS installation.

I have been one of those who are lucky to have worked on RSX-11M. I was responsible to install a PDP-11 with RSX-11M based control system in India for a German Robotic Welding machine for a mini-truck chassis. The RSX-11m based system with the control software worked so well that we had our first maintenance call 5 years after the system was commissioned and the fault was not with the basic computer system but with one of the associated I/o cards. Later I got so much fascinated with RSX-11M as an OS ( with a very good documentation from DEC) that I designed an RTOS based upon the data structures of RSX-11M and used it in the embedded products of my company.

I don't actually remember what EDGAR stood for, but knowing the engineers responsible for this prank, it was something we couldn't print anyway. But the suggestions are great.
One of the best "retaliations" for this individual came when he was away on a business trip. The engineers ducted the packing material chute from production to his office and filled it to the top with stryofoam peanuts. He had to get a ladder, pull up the ceiling tiles and shovel his way in from the top just to get the door open.

Please stop casting derision on the venerable PDP11 and RSX 11. I recently retired a PDP11, RSX 11M system that ran a conveyor system that had been installed back in the early 1980's. The PDP11 was not the point of failure, obtaining parts for the controls systems long out of production was the problem. The Senior Engineer's password was "NotAPC".
As for EDGAR - Enter Dave, Get Accumulated Results

Locking a cat in a filing cabinet and scaring the secretary to death (being the sixties, we had secretaries, not administration assistants). Just a little multivibrator oscillator with regen/saturation as I recall. No live cats were used in this operation.